If you have a sword who has been damaged in battle, you must repair them. The swords will not regain health automatically over time, they must be repaired back to full health and this will take time and materials. Time and materials needs also differ depending on the sword type, how much damage they have taken, and their level. You will be shown repair time and materials required before repairs begin and you must confirm you want the sword repaired.
Once a repair has begun, you cannot stop it. There is an item called a Help Token, that you can use to skip the time requirement and automatically repair the sword. Help Tokens can be applied before or during the repair. If you do not have a Help Token, you must wait until the repair time has elapsed.
While a sword is being repaired, you cannot refine him nor equip him with troops or horses. A team that has a sword who is being repaired in it cannot go to battle or expedition. You must replace the repairing sword with an available one in order to make the team active again.
When you start the game, you will have two slots for sword repairs. You can purchase up to two more through the merchant.